[R-390] Possible source for isolation transformers?

[Bob Young]

My wife is from Lima, Peru and I bought a huge 220V-110V transformer very 
cheap there, I used it to power everything I had brought over including 2 
bass guitar amplifiers. I think it had a capacity of 1500 watts. (lived 
there for almost a year). I don't think it was an autotransfomer either, 
looked (and weighed) like a traditional transformer. They are available 
everywhere in Lima in hardware stores and other places. I would assume the 
same is true in most other countries given the amount of Americans who 
travel.

Bob
KB1OKL


>From: Barry <n4buq at knology.net>
>Reply-To: n4buq at knology.net
>To: r-390 at mailman.qth.net
>Subject: Re: [R-390] Possible source for isolation transformers?
>Date: Wed, 04 Jul 2007 09:04:47 -0400
>
>I'm curious as just to what's under the hood.  I suppose they can get away 
>with calling an autotransformer simply a transformer.  If it is truly a 
>transformer, though, I can't see how they can sell them at that price.
>
>If they are autotransformers, is this a better solution for 220V-110V 
>conversion than the little voltage converters available?  I belong to a 
>list of folks who have (or will) travel overseas and several ask from time 
>to time about what to use to power their various 120V appliances (chargers, 
>etc.) while overseas.  While a small converter is fine for charging a 
>battery or running a small device, I keep having to warn folks who want to 
>power their blowdryers, etc., from them.  I thought these might be a better 
>alternative; however, they'd certainly need the 1500W or larger unit for 
>such applications.  I know blowdryers are available in 220V models and 
>that's probably the best way to go, but most folks aren't going to do that 
>so I keep looking for better options.  I've explained the "best" solution 
>is a step-down transformer, but it's unlikely anyone will want to pack one 
>of sufficient size in their luggage.
>
>I know its OT, but if anyone has any thoughts on this, I'd appreciate a 
>reply either on or off the list.
>
>Thanks,
>
>Barry - N4BUQ
>
>
>  On Wed Jul  4  7:51 , "Steve Hobensack"  sent:
>
> >Transformers for this application are almost always autotransformers. 
>They
> >are smaller for a given wattage because there is only one winding (with
> >tap), and the common part of the winding can be downsized. They will not
> >function for isolation. They can be used either for step-up or step-down.
> >...Steve...N8YE
> >
> >Knowing the leaky filters won't run on GFI circuits and are probably not
> >all that safe when used on non-GFI or non-isloated circuits, I think
> >some folks may be looking for isolation transformers.  While searching
> >for voltage converters for overseas travel, I found these:
> >
> >http://www.eastwestintl.com/proddetail.asp\?pid=2625
> >
> >They state that they are transformers, not just converters, and that
> >they can be configured to run either 110-220 or 220-110.  I wonder if
> >these could also be wired for 120-120 and used as an isolation
> >transformer.  If not, if someone has 220V in the shop, it might be a
> >good way to power an R390[A].
> >
> >If you back up a page, they have a variety of transformers ranging from
> >100W on up.
> >
> >Just thought I'd pass this along.
> >
> >Barry - N4BUQ
>
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